Efficient Improvement the Production of Recombinant Nitrilase by Optimizing Culture Conditions Using Response Surface Methodology (RSM)

A nitrilase from Acidovorax facilis 72W for efficient converting aliphatic dinitriles to cyanocarboxylic acids was over-expressed in E. coli BL21(DE3). The culture conditions were optimized by Response Surface Methodology (RSM) to improve the production of target enzyme in this study. The optimized result is that starch concentration 23.55 g/L, corn paste and yeast extract 20.15 g/L (1:1), and IPTG 0.18 mM. The model was confirmed by validating experiments and the obtained nitrilase activity (202.0 U/L) was very close to the predicted activity (201.9 U/L). The specific nitrilase activity under optimized media is 1.75 times higher than that in LB media. For 1 M substrate, the conversion was increased from 70% to 97% after 6 h reaction by changing cells cultivated from initial LB media to optimal media.